Molar Specimens Research Articles

Insights into archaeological and modern neotropical biomes: Examining diet and shape variation through white-tailed deer lower third molar

The white-tailed deer (Odocoileus virginianus Zimmermann 1780) holds significant ecological importance across the Americas, both historically and in modern times. This species ranges from southern Canada to Brazil and exhibits polytypic characteristics, adapting well to diverse habitats including temperate, subtropical, semi-arid, rainforest, and savanna environments. In paleontology and archaeology, the comparison of dental characteristics between extant mammal species with known diets is commonly employed to infer the feeding behaviors of their ancient counterparts. This method assumes that extant and fossil species share similar dietary preferences, aiding in the identification of past environmental contexts. Consequently, we employed a multiproxy approach, combining the study of dental wear and 2D geometric morphometrics, to investigate potential relationships between molar shape, diet, and biomes among extant white-tailed deer populations across the Americas. Our analysis included a comparison with archaeological data from Panama. We sampled 274 extant lower second molar specimens for micro- and mesowear analysis, along with 105 lower third molar specimens from natural science museums for 2D geometric morphometric analysis. These were compared with a sample of 65 archaeological specimens from Panama. Our findings revealed distinct variations in the shape of lower m3 molars among extant white-tailed deer populations across different biomes, with notable differences observed in the archaeological samples as well. Micro- and mesowear analyses also indicated biome-related differences, suggesting a general browsing diet for white-tailed deer with nuanced variations across biomes. Mesowear analysis further suggested a dietary spectrum ranging from pure browsers to browser-mixed feeders. These findings offer valuable insights for the interpretation of fossil deer specimens recovered from archaeological sites.

Effects of dental tissue substructure and size on fracture strengths of lithium disilicate and zirconia ceramics

We aimed to assess the effects of standard resin preparation models with five different thicknesses of occlusal surface on the fracture strengths of zirconia (ZrO2) and lithium disilicate glass ceramics. The specimens of 10 first maxillary molars collected between January 2019 and January 2020 were selected. Standard mathematical models were formed after scanning the resin matrices using software. The full crowns with five different thicknesses of occlusal surface were established, among which the molar specimens prepared by ZrO2 glass ceramic composites alone were assigned into ZrO2 group (n=5, 40 specimens) while those prepared using ZrO2-lithium disilicate glass ceramic composites were allocated into ZTCLDC group (n=5, 40 specimens). When the thickness of glass-ceramic full crowns was 0.5, 0.8, 1.0, 1.2 and 1.5 mm, the fracture load of the specimens in ZTCLDC group was not significantly different from that in ZrO2 group, and there was no significant difference in the three-point flexural strength between ZTCLDC group and ZrO2 group (P>0.05). The fracture toughness was not significantly different between the two groups in the case of the thickness of glass-ceramic full crown at 0.5, 0.8, 1.0, 1.2 and 1.5 mm (P>0.05). The thickness was positively correlated with fracture load, three-point flexural strength and fracture toughness (P<0.05). The fracture strength of lithium disilicate and ZrO2 ceramics is directly proportional to the thickness of ZrO2 and ZTCLDC crowns.

Quantitative evaluation of the impact of indoor relative humidity on deposition of aerosols generated during tooth grinding in a real-world clinical setting.

Exposure to aerosol particles generated from tooth grinding has a negative impact on the health of dental personnel. The aim of this study was to quantitatively analyze the impact of indoor relative humidity (IRH) on the deposition of these suspended particles in a well-controlled dental environment. In this study, a humidity control system was employed to effectively regulate and maintain indoor relative humidity (IRH). A novel computer-assisted numerical control system was developed to pre-treat the molar specimens, and accurately simulate clinical tooth grinding procedures. Each procedure was performed in triplicate, with an online real-time particle counter (ORPC; TR-8301, TongrenCo.) measuring aerosol production. All testing devices were controlled remotely. The data obtained were statistically analyzed using descriptive statistics and non-parametric tests (Kruskal-Wallis/ Dunn's post hoc test with Bonferroni correction, p < 0.05). The findings showed that with increasing IRH, the maximum peak concentration of aerosol particles decreased by 397% from 6.51 × 107 particles/m3 at 30% to 1.64 × 107 particles/m3 at 80%. The Kruskal-Wallis test results indicated a statistically significant effect of IRH on the aerosol increment (p < 0.05). Increasing the IRH level can effectively promote the deposition of aerosol particles, with a return to baseline within 15min after reaching 60% or above. Our study suggested that maintaining IRH above 70% during the cleaning process, allowing natural recovery to ambient humidity levels within 15min after cleaning, and taking basic precautions, may lead to an adequate reduction in the possible health risks of aerosol contamination.

Assessment of Wear Resistance in Tooth-Colored Materials for Primary Molar Crown Restoration in Pediatric Dentistry

The objective of this study was to assess the wear resistance of tooth-colored materials used in crown restoration for primary molars with a chewing simulator. In this study, four groups-three experimental groups and one control group-were included. They consisted of three-dimensional (3D) printed resin crowns (NextDent and Graphy), milled nano-hybrid ceramic crowns (MAZIC Duro), and prefabricated zirconia crowns (NuSmile). Twelve mandibular second molar specimens were prepared from each group. In the wear experiment, 6.0 × 10&lt;sup&gt;5&lt;/sup&gt; cycles were conducted with a force of 50 N, and a 6 mm-diameter steatite ball was used as an antagonist. The amount of wear was calculated by comparing the scan files before and after the chewing simulation using 3D metrology software, and the worn cross-section was confirmed by scanning electron microscopy (SEM). The resin and ceramic groups did not exhibit any statistically significant differences. However, compared to other crown groups, the zirconia crown group demonstrated notably reduced levels of wear (&lt;i&gt;p&lt;/i&gt; &lt; 0.05). In SEM images, layers and cracks were observed in the 3D-printed resin crown groups, which differed from those in the other groups.

Hydatidiform mole in Tuzla Canton

AbstractAim Hydatidiform mole is a rare pregnancy disorder, with wide variety of reported incidence. The aim of the study was to estimate the incidence of hydatidiform moles (HM) in Tuzla Canton, specifically partial (PHM) and complete (CHM) forms.Material and methods All cases of HM that have been diagnosed at the University Clinical Center, Tuzla, between January 2011 and December 2015 were registered. The overall incidence of HM, as well as the incidence of PHM and CHM was calculated using the Tuzla Canton's live birth rate during the study period. A second review of tissue slides and p57 immunohistochemistry (IHC) staining was performed to determine the validity of the criteria for the diagnosis and distinction of the molar specimens. Results There have been 256 cases of HM, 243 cases of PHM, 12 cases of CHM, and one case of unspecified HM. The average incidence of PHM was estimated at 11.03/1,000 and CHM at 0.54/1,000 live births. A second pathologist review revealed one PHM as a non-molar specimen, confirmed all CHM and identified an unknown HM as a PHM. Out of the 50 randomly chosen samples of PHM, p57 expression confirmed the diagnosis in 48 cases, disclosed one case as unrecognized CHM, and one sample showed discordant staining. IHC staining for p57 approved the diagnosis for all cases of CHM.Conclusion: HM incidence reporting remains a challenge due to the study design. p57 immunohistochemistry confirmed the strong validity of histopathological criteria in the diagnosis of CHM.

The IL-1β-p65 axis stimulates quiescent odontogenic epithelial cell rests via TGF-β signalling to promote cell proliferation of the lining epithelia in radicular cysts: A laboratory investigation.

Cyst formation of the jaws is frequently accompanied by the proliferation of odontogenic epithelial cells located in the periodontal ligament (PDL), which consists of heterozygous cells and includes the most fibroblasts. The lining epithelium of radicular cyst, an odontogenic cyst of inflammatory origin, is derived from the proliferation of the remnants of the Hertwig epithelial root sheath (odontogenic epithelial cell rests of Malassez; ERMs) in the PDL. ERMs are maintained at a lower proliferative state under physiological conditions, but the regulatory mechanisms underlying the inflammation-dependent enhanced-proliferative capabilities of ERMs are not fully understood. The aim of this study was to evaluate the effects of cytokine pathway association between TGF-β signalling and IL-1β signalling on the regulation of odontogenic epithelial cell proliferation using radicular cyst pathological specimens and odontogenic epithelial cell lines. Immunofluorescence analyses were performed to clarify the expression levels of Smad2/3 and Ki-67 in ERMs of 8-week-old mouse molar specimens. In radicular cyst (n = 52) and dentigerous cysts (n = 6) specimens from human patients, the expression of p65 (a main subunit of NF-κB), Smad2/3 and Ki-67 were investigated using immunohistochemical analyses. Odontogenic epithelial cells and PDL fibroblastic cells were co-cultured with or without an inhibitor or siRNAs. Odontogenic epithelial cells were cultured with or without TGF-β1 and IL-1β. The proliferative capabilities and Smad2 phosphorylation levels of odontogenic epithelial cells were examined. Immunohistochemically, Smad2/3-positivity was increased, and p65-positivity and Ki-67-positivity were decreased both in ERMs and in the epithelial cells in dentigerous cysts, a non-inflammatory developmental cyst. In contrast, p65-positive cells, along with the expression of Ki-67, were increased and Smad2/3-positive cells were decreased in the lining epithelia of radicular cysts. Co-culture experiments with odontogenic epithelial cells and PDL fibroblastic cells revealed that PDL cells-derived TGF-β1/2 and their downstream signalling suppressed odontogenic epithelial cell proliferation. Moreover, TGF-β1 stimulation induced Smad2 phosphorylation and suppressed odontogenic epithelial cell proliferation, while IL-1β stimulation reversed these phenotypes through p65 transactivation. These results suggest that IL-1β-p65 signalling promotes odontogenic epithelial cell proliferation through suppressing TGF-β-Smad2 signalling, which would be involved in the pathogenesis of radicular cysts.

Roughness and Microhardness of Demineralized Enamel Treated with Resinous Infiltrants and Subjected to an Acid Challenge: An in vitro Study

Background: Resinous infiltrating has proven effective in arresting incipient caries lesions. Objective: This study aimed to assess the penetration depth of an experimental resin-infiltrant (75% - TEGDMA, 25% - Bis-EMA, 1% - EDAB, 0.5% camphorquinone), compare it with commercial infiltrant Icon®, and analyze the surface-roughness and microhardness of the resin-materials infiltrated into tooth specimens, before and after pH cycling. Methods: To assess penetration depth, sound third molar specimens were submitted to ten de-remineralization cycles for incipient carious lesion induction and were then randomly divided into 2 groups (n=3): (I) Experimental Infiltrant (EI) and (II) Commercial Infiltrant Icon (CI). After resin infiltration into specimens, qualitative Confocal Fluorescence Microscopy images were captured. For roughness and microhardness assessment, new specimens were demineralized, then randomly divided into two groups (n=20): (I) Experimental Infiltrant (EI) and (II) Commercial Infiltrant Icon (CI) and submitted to roughness and microhardness readouts at the following time-intervals: (T1) sound tooth, (T2) white-spot caries lesion, (T3) resin material that infiltrated, and (T4) resin material that infiltrated and was exposed to pH-cycling. In statistical analyses, generalized linear models of repeated measures in time were applied, with a significance level of 5%. Results: The experimental infiltrant penetrated the carious lesion and exhibited lower roughness values after its application, even after pH cycling, similar to the CI. The microhardness value of the EI group was significantly lower in the last three-time intervals evaluated compared to CI. Conclusion: Experimental resin infiltrant was efficient in penetrating white spot lesions and reducing surface roughness; however, it did not increase surface microhardness.

Twenty-month Performance of a Universal Bonding System on Simulated-challenged Dentin Substrates Pretreated with Chlorhexidine.

Since the use of dentin antiproteolytic agents with universal adhesives (UAs) can potentially degrade the bonding interface, this study evaluated bond strengths with and without chlorhexidine (CHX) on variously altered dentin surfaces for up to 20 months. Human molar specimens (n=20) were categorized by substrates as S=sound, E=eroded, and C=carious, and by pretreatment as W=water or CHX. These specimens were subjected to micro-tensile bond strength (μTBS) testing at 24 hours, 6 months, and 20 months, after 30 seconds of pretreatment with CHX or W, followed by self-etching and bonding (Adper Single Bond Universal, 3M ESPE). Modes of failure were assessed using optical microscopy (40×) and scanning electron microscopy (SEM), and the results were analyzed by 3-way ANOVA and Tukey's statistical tests (α=0.05). Substrate (p<0.001), pre-treatment (p=0.0413), and time (p<0.0001) were statistically significant. The sound-dentin group in initial time (W=39.27/CHX=40.55) yielded the higher μTBS values (MPa) in comparison with altered substrates pre-treated with CHX (E-CHX=19.84; C-CHX=18.24) after 20 months, which showed the lowest values. Under SEM analysis, heterogeneous patterns appeared in the hybrid layer of the CHX-treated group, particularly in the altered substrates. Bond strength to dentin decreased over a period of 20 months using UA with 10-methacryloyloxydecyl-dihydrogen phosphate (MDP) in self-etching mode. Substrates altered by erosion or caries have impaired adhesion and associated clinical use of UA with MDP and CHX should be avoided.

Epidemiological and morphological pattern of complete hydatidiform mole in Aminu Kano Teaching Hospital, Kano Northwestern Nigeria

Background: Complete hydatidiform mole (CHM) is the most common form of non-neoplastic gestational trophoblastic diseases (GTD) that is associated with progression to choriocarcinoma without prompt intervention. The objectives of this study is to morphologically analyze all cases of complete hydatidiform mole in Aminu Kano Teaching Hospital using set down criteria, look at the epidemiological pattern and compare with similar studies in order to stimulate proper identification from other forms of moles, hence reduce morbidity and mortality associated with the known complication of progressing to deadly Choriocarcinoma. Material and Methods: This was a retrospective study of all molar specimens submitted to Histopathology Pathology Department of Aminu Kano Teaching Hospital, Kano between 1st January 2015 and 31st December 2016. Formalin-fixed paraffin-embedded tissue blocks and corresponding Haematoxylin and Eosin (H&amp;E) stained slides were retrieved. Cases with final diagnosis of complete mole were selected for further detailed microscopic evaluations. The collected data were presented using simple frequency tables and figures including photomicrographs of representative lesions. Results: There were sixty-seven cases of complete hydatidiform mole during the study period out of the 61,780 deliveries, giving an approximate incidence of 1:1000 deliveries in Kano metropolis and its environs. The peak incidence was observed in women between 20- 24 years of age with majority presenting between 11-14weeks of pregnancy. The ratio of complete to partial mole was approximately 3:1. Constant morphologic features associated with CHM includes; villous enlargement, trophoblastic hyperplasia, round shape chorionic villi and fibromyxoid stroma. Least prominent feature of CHM is myxoid stromal type. Conclusion: Complete hydatidiform occurs commonly in the gestational ages of between eleven to fourteen weeks; need histopathologic evaluations and prompt intervention to avoid consequences of both immediate complication such as invasive mole and long-term complication of choriocarcinoma. Keywords: Hydatidiform Mole, Complete Mole, Choriocarcinoma

Microtensile Bond Strength of Bioactive Pit and Fissure Sealants Bonded to Primary and Permanent Teeth.

Background: Sealing occlusal pits and fissures is an effective preventive measure against dental caries. Pit and fissure sealants (PFS) should be strongly bonded to the teeth to prevent partial or complete loss of the sealant, which may limit its preventive effect. Objective: The objective of the study was to compare the microtensile bond strength (μTBS) of bioactive resin-based sealants (Bio-RBS) and resin-based sealants (RBS), with and without the use of a bonding agent, to the enamel of primary and permanent teeth. Methods: One hundred and twenty caries-free primary molar specimens and 120 permanent molar specimens were divided to eight groups (30 specimens per group), both primary and permanent teeth were sealed with a Bio-RBS BioCoatTM (Premier®, Plymouth Meeting, PA, USA) or with a RBS ClinproTM (3M ESPE, Saint Paul, MN, USA), with or without the use of a bonding agent (Prime & Bond NT; Dentsply, Inc., Charlotte, NC, USA). Half the specimens were aged with 5000 thermal cycles, and all specimens were tested for the μTBS and failure mode. Results: The mean μTBS of aged Bio-RBS was higher in permanent teeth than primary teeth, and the aging process reduced the μTBS of RBS more than that of Bio-RBS. Moreover, the addition of a bonding agent improved the μTBS of aged RBS in permanent teeth. Conclusion: We concluded that Bio-RBS exhibit superior μTBS than RBS when applied to permanent teeth.

Pulpal Response to the Combined Use of Mineral Trioxide Aggregate and Iloprost for Direct Pulp Capping

Purpose: The present study aims to assess the combined effects of mineral trioxide aggregate (MTA) and iloprost when used as a pulp capping material on pulpal inflammation and tertiary dentin formation compared with MTA and iloprost alone in rat molar teeth. Methods: Eighty maxillary first molar rat teeth were exposed and capped with iloprost solution, MTA, or MTA mixed with iloprost (MTA-iloprost). The cavities were then filled with resin-modified glass ionomer. The cavity was restored with glass ionomer without the use of pulp capping agent in the control group. The rats were sacrificed after one and four weeks. Block sections of the molar specimens were prepared and subjected to hematoxylin and eosin staining for evaluation. Statistical analysis was done using the Kruskal–Wallis test, followed by Dunnett’s test. Results: At week one, the control group showed significantly more severe pulpal inflammatory reactions than the iloprost (p = 0.00), MTA (p = 0.04), and MTA-iloprost (p = 0.00) groups. Hard tissue formation was commonly found in the iloprost, MTA, and MTA-iloprost groups. After four weeks, pulpal tissue degeneration was observed in the control group. Complete hard tissue barriers were found in 50%, 72.7%, and 77.8% of the specimens in iloprost, MTA, and MTA-iloprost groups, respectively, with no significant differences among the experimental groups. The dentinal tubule patterns were mostly regular in the MTA-iloprost group and irregular in the iloprost and MTA groups. Conclusions: The application of iloprost, MTA, and MTA-iloprost as a pulp capping material resulted in similar pulpal responses in the mechanically exposed pulp of rat molars. Therefore, mixing MTA with iloprost might not be clinically significant.

Serotonin contributes to the in vitro production of a biomimetic enamel-like material from reprogrammed oral epithelial keratinocytes.

To evaluate the role of serotonin in the development of a biomimetic enamel-like material in vitro. Immortalized murine oral keratinocytes raised from adult mouse mucosa were cultured in vitro. In addition, specimens incorporating molar tooth buds harvested from mice were included in our studies. We used cell-based scaffold-free tissue engineering to assemble three-dimensional (3D) organoids into complex tissue constructs that closely emulate the complexity of adult enamel. We also analysed mouse molar specimens using immunohistochemistry for serotonin expression as well as its cognate receptor. TGF-β1-reprogrammed murine oral keratinocytes formed organoids that laid down an amelogenin-rich protein matrix when grown as three-dimensional (3D) cultures in the presence of serotonin. Following mineralization, the newly formed crystals were densified under pressure and vacuum to produce a biomimetic enamel-like material that demonstrated parallel alignment of hydroxyapatite crystals with some interspaced residual organoid matter into enamel prism-like structures conferring size, mechanical properties comparable to tooth enamel, including light translucency. Serotonin expression was localized by immunohistochemistry proximal to the enamel organ of developing molar buds. Moreover, serotonin HTRb2 receptor expression was localized on ameloblasts within the enamel organ proximal to the area where serotonin was immunolocalized. Our results demonstrate that serotonin is inductive in the development of a biomimetic enamel-like material from reprogrammed oral epithelial keratinocytes in vitro. The facileness of harvesting adult somatic cells together with the versatility of our approach offers exciting opportunities to address regenerative challenges linked to lost enamel.

Differential expression of P63, P27, P57, Ki-67, and CD146 in hydropic and molar pregnancies.

To investigate the expressions of immunohistochemical markers P63, P27, P57, Ki-67 and CD146 in hydropic and molar specimens in order to explore their role in the pathogenesis of molar gestations. The retrospective study was conducted at the Kırıkkale Medical University, Turkey, and comprised data from 2011 to 2018 related to patients with a definitive pathological diagnosis of hydropic abortus, complete hydatidiform moles and partial hydatidiform moles. Immunoreactivity using antibodies against P63, P27, P57, Ki-67 and CD146 was scored by evaluating the percentage of distinctly stained cells. Data was analysed using SPSS 15. Of the 37 specimens, 10(27%) were hydropic abortus, 17(46%) partial hydatidiform moles and 10(27%) complete hydatidiform moles. Patients with complete hydatidiform moles severe cytologic atypia in CD146-positive extravillous trophoblastic column and florid syncytiotrophoblast proliferation. P57 immunostaining was negative in 9(90%) patients with complete hydatidiform moles, whereas all patients in the two other groups showed positive immunostaining, and they also showed P63 and Ki-67 overexpression in cytotrophoblasts. P27 was expressed in differentiated, non-dividing syncytiotrophoblasts but did not yield any diagnostic aid. The proliferative activity location varied between molar and nonmolar pregnancies.

Discovery of inverted discordant p57 expression in random clusters of dysmorphic chorionic villi of third trimester placentas suggests a more common occurrence of such phenomenon than initially described

IntroductionInverted discordant p57 expression in chorionic villi, characterized by a loss of nuclear staining in cytotrophoblast with retained staining in villous stromal cells, is rarely described. Following an incidental finding of such peculiar staining pattern in rare clusters of dysmorphic chorionic villi (DCV) in a perinatal autopsy case, we reviewed our archived cases of third trimester placentas with DCV to systematically analyze these curious foci. MethodsHistopathological features and p57 expression of 26 placentas with DCV were carefully studied by light microscopy and p57 immunohistochemistry. p57 pattern of expression was correlated with a comprehensive list of maternal, fetal, and placental features to reveal potential associations. ResultsInverted discordant p57 expression was observed in 17/26 (65.4%) cases, encompassing all cases with aberrant p57 immunostaining in this series. Among the many features investigated, only the focality (occurring as a single focus) of DCV (Fisher's exact test, p = 0.008) and small cluster size of ≤30 villi (Fisher's exact test, p = 0.034) correlated significantly with inverted discordant p57 staining. Other common features of DCV with inverted discordant p57 expression include larger villous size compared with surrounding tertiary villi (13/17, 76.4%), prominent but not hyperplastic and focally to moderately hyperplastic syncytiotrophoblast (17/21, 80.9%), abnormal shapes/irregular contours (17/22, 77.3%), and markedly hypovascular villous stroma (11/17, 64.7%). No distinctive maternal or fetal features were observed. DiscussionInverted discordant p57 expression in DCV of third trimester placentas is likely underreported, and might not be an unusual occurrence outside of suspected molar specimens.

Refined diagnosis of hydatidiform moles with p57 immunohistochemistry and molecular genotyping: updated analysis of a prospective series of 2217 cases.

Immunohistochemical analysis of p57 expression and molecular genotyping accurately subclassify molar specimens into complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM) and distinguish these from nonmolar specimens. Characteristics of a prospective series of potentially molar specimens analyzed in a large gynecologic pathology practice are summarized. Of 2217 cases (2160 uterine, 57 ectopic), 2080 (94%) were successfully classified: 571 CHMs (570 uterine, 1 ectopic), 498 PHMs (497 uterine, 1 ectopic), 900 nonmolar (including 147 trisomies, 19 digynic triploids, and 4 donor egg conceptions), and 56 androgenetic/biparental mosaics; 137 were complex or unsatisfactory and not definitively classified. CHMs dominated in patients aged < 21 and >45 years and were the only kind of molar conception found in the latter group. Of 564 successfully immunostained CHMs, 563 (99.8%) were p57-negative (1 p57-positive [retained maternal chromosome 11] androgenetic by genotyping). Of 153 genotyped CHMs, 148 (96.7%) were androgenetic (85% monospermic) and 5 were biparental, the latter likely familial biparental hydatidiform moles. Of 486 successfully immunostained PHMs, 481 (99%) were p57-positive (3 p57-negative [loss of maternal chromosome 11], 2 unknown mechanism). Of 497 genotyped PHMs, 484 (97%) were diandric triploid (99% dispermic) and 13 were triandric tetraploid (all at least dispermic). Of 56 androgenetic/biparental mosaics, 37 had a p57-negative complete molar component (16 confirmed as androgenetic by genotyping). p57 expression is highly correlated with genotyping, serving as a reliable marker for CHMs, and identifies molar components and androgenetic cell lines in mosaic conceptions. Correlation of morphology, p57 expression, genotyping data, and history are required to recognize familial biparental hydatidiform moles and donor egg conceptions, as the former can be misclassified as nonmolar and the latter can be misclassified as dispermic CHM on the basis of isolated genotyping results.

Hominin dental remains from the Pliocene localities at Lomekwi, Kenya (1982–2009)

Increasing evidence for both taxonomic diversity and early stone manufacture during the Pliocene highlights the importance of the hominin fossil record from this epoch in eastern Africa. Here, we describe dental remains from Lomekwi (West Turkana, Kenya), which date from between 3.2 and 3.5 Ma. The sample was collected between 1982 and 2009 and includes five gnathic specimens and a total of 67 teeth (mostly isolated permanent postcanine teeth). Standard linear dimensions indicate that, although the Lomekwi teeth are relatively small, there is broad overlap in size with contemporary Australopithecus afarensis and Australopithecus deyiremeda specimens at most tooth positions. However, some dental characters differentiate this sample from these species, including a relatively large P4 and M3 compared with the M1, a high incidence of well-developed protostylids, and specific accessory molar cuspules. Owing to a lack of well-preserved tooth crowns (and the complete absence of mandibular teeth) in the holotype and paratype of Kenyanthropus platyops, and limited comparable gnathic morphology in the new specimens, it cannot be determined whether these Lomekwi specimens should be attributed to this species. Attribution of these specimens is further complicated by a lack of certainty about position along the tooth row of many of the molar specimens. More comprehensive shape analyses of the external and internal morphology of these specimens, and additional fossil finds, would facilitate the taxonomic attribution of specimens in this taxonomically diverse period of human evolution.

Palynological analysis of dental calculus from Pleistocene proboscideans of southern Brazil: A new approach for paleodiet and paleoenvironmental reconstructions

The proboscidean Notiomastodon platensis is widely recognized in the Pleistocene of Brazil, but direct evidence for its feeding behavior is scant. In this paper, we report palynological assemblages preserved in dental calculi to infer dietary preferences and habitats. Molar specimens (m1 and M3/m3) with significant calculus accumulation were examined from localities along the Coastal Plain (CPRS) and the Campanha region (western state in Pampa biome) in Rio Grande do Sul state, southern Brazil. Palynomorphs obtained from calculus were identified with light microscopy, and we applied species distribution modelling (SDM) for arboreal/shrub pollen taxa to investigate the environmental contexts for proboscideans during the Last Interglacial (LIG, 120 ka BP) and Last Glacial Maximum (LGM, 21 ka BP). Pollen assemblages indicate a generalist diet for N. platensis, and corroborate previous paleoecological studies. N. platensis from CPRS showed two patterns: the subadult individual was a specialized browser in wooded habitats, inferred from pollen taxa dominated by arboreal species (mainly Myrtaceae), while mature/senile adult individuals were dominantly grazers to mixed-feeders in open habitats inferred from herbaceous pollen (mainly Cyperaceae) mixed with woody elements. For the Campanha region, diet interpretation is difficult due to the absence of pollen; however, Poaceae phytoliths indicate that grasses may have been important food items, notably pooid C3 grasses. N. platensis potentially accessed a more heterogeneous environment with mixed open grasslands and forests around the LIG interval because of the larger extension of forest at the time. Grassland landscapes could have been more foraged by proboscideans around the LGM given the dry and cold climate conditions, which resulted in a northward retraction of forest.

Paleoecological implications of the first prehistoric record of water vole (Microtus richardsoni) from Washington state, USA

AbstractRemains of the North American water vole (Microtus richardsoni) have previously been recovered from late Pleistocene and Holocene deposits in southwestern Alberta, western Montana, and north-central Wyoming. All are within the historically documented modern range of the metapopulation occupying the Rocky Mountains; no ancient remains of this large microtine have previously been reported from the metapopulation occupying the Cascade Range. Four lower first molar specimens from the late Holocene Stemilt Creek Village archaeological site in central Washington here identified as water vole are from the eastern slope of the Cascade Range and are extralimital to the metapopulation found in those mountains. There is no taphonomic evidence indicating long-distance transport of the teeth, and modern trapping records suggest the local absence of water voles from the site area today is not a function of sampling error. The precise age of the Stemilt Creek Village water voles is obscure but climate change producing well-documented late Holocene advances of nearby alpine glaciers could have created habitat conditions conducive to the apparent modest shift in the range of the species represented by the remains.

Hydatidiform Moles: Ancillary Techniques to Refine Diagnosis.

Distinction of hydatidiform moles from nonmolar specimens and subclassification of hydatidiform moles as complete hydatidiform mole versus partial hydatidiform mole are important for clinical practice and investigational studies. Risk of persistent gestational trophoblastic disease and clinical management differ for these entities. Diagnosis based on morphology is subject to interobserver variability and remains problematic, even for experienced gynecologic pathologists. To explain how ancillary techniques target the unique genetic features of hydatidiform moles to establish diagnostic truth, highlight the issue of diagnostic reproducibility and importance of diagnostic accuracy, and illustrate use of p57 immunohistochemistry and polymerase chain reaction-based DNA genotyping for diagnosis. Sources are the author's 10-year experience using ancillary techniques for the evaluation of potentially molar specimens in a large gynecologic pathology practice and the literature. The unique genetics of complete hydatidiform moles (purely androgenetic), partial hydatidiform moles (diandric triploid), and nonmolar specimens (biparental, with allelic balance) allow for certain techniques, including immunohistochemical analysis of p57 expression (a paternally imprinted, maternally expressed gene) and genotyping, to refine diagnoses of hydatidiform moles. Although p57 immunostaining alone can identify complete hydatidiform moles, which lack p57 expression because of a lack of maternal DNA, this analysis does not distinguish partial hydatidiform moles from nonmolar specimens because both express p57 because of the presence of maternal DNA. Genotyping, which compares villous and decidual DNA patterns to determine the parental source and ratios of polymorphic alleles, distinguishes purely androgenetic complete hydatidiform moles from diandric triploid partial hydatidiform moles, and both of these from biparental nonmolar specimens. An algorithmic approach to diagnosis using these techniques is advocated.

Analysis of p53 expression in partial hydatidiform mole and hydropic abortion

Gestational trophoblastic disease (GTD) is a heterogeneous group of disorders characterized by abnormal trophoblast tissue. Molar and non-molar hydropic placental changes are the most common forms of GTD. Differential diagnosis of GTD is sometimes problematic. Recently, p53 expression was identified as a good marker for distinguishing GTD types. Comparison of p53 expression in partial hydatidiform mole (PHM) and hydropic abortion. In this prospective cross-sectional study, molar and non-molar hydropic pregnancy specimens were collected. Immunohistochemical staining, based on the Labeled Streptavidin Biotin (LSAB) technique, was carried out on multiple 4 mm paraffin block sections prepared from formalin-fixed trophoblastic tissues. Polymer-based Envision was used to assess p53 tumor suppressor protein immunoreactivity. p53 expression was then compared between both groups. In the study, 40 patients were included: 20 with confirmed PHM and 20 with hydropic pregnancy. p53 protein was positive in 60% of patients with PHM and 25% of patients with hydropic pregnancy. The p53 positive rate was significantly higher in patients with PHM (p = 0.027). Moreover, patients with PHM had a significantly high grade of staining (p<0.001). Our findings indicate that immunohistochemical analysis of p53 protein can be used to distinguish PHM and hydropic pregnancy.